fix(rsc): generate sourcemaps for code transforms

packages/plugin-rsc/e2e/sourcemap.test.ts

@@ -0,0 +1,25 @@
+import { expect, test } from '@playwright/test'
+import { x } from 'tinyexec'
+import { setupInlineFixture } from './fixture'
+
+test.describe('sourcemap', () => {
+  const root = 'examples/e2e/temp/sourcemap'
+
+  test.beforeAll(async () => {
+    await setupInlineFixture({
+      src: 'examples/starter',
+      dest: root,
+    })
+  })
+
+  test('build without broken sourcemap warnings', async () => {
+    const result = await x('pnpm', ['build', '--sourcemap'], {
+      nodeOptions: { cwd: root },
+    })
+
+    expect(result.exitCode).toBe(0)
+    expect(result.stdout + result.stderr).not.toContain(
+      'Sourcemap is likely to be incorrect',
+    )
+  })
+})

packages/plugin-rsc/src/plugin.ts

@@ -331,7 +331,12 @@ export function vitePluginRscMinimal(
           if (code.includes('__vite_rsc_raw_import__')) {
             // inject dynamic import last to avoid Vite adding `?import` query
             // to client references (and browser mode server references)
-            return code.replace('__vite_rsc_raw_import__', 'import')
+            const output = new MagicString(code)
+            output.replace('__vite_rsc_raw_import__', 'import')
+            return {
+              code: output.toString(),
+              map: output.generateMap({ hires: 'boundary' }),
+            }
           }
         },
       },
@@ -1247,11 +1252,15 @@ export function createRpcClient(params) {
               BUILD_ASSETS_MANIFEST_NAME,
             ),
           )
-          code = code.replaceAll(
+          const output = new MagicString(code)
+          output.replaceAll(
             'virtual:vite-rsc/assets-manifest',
             () => replacement,
           )
-          return { code }
+          return {
+            code: output.toString(),
+            map: output.generateMap({ hires: 'boundary' }),
+          }
         }
         return
       },
@@ -1396,13 +1405,17 @@ function globalAsyncLocalStoragePlugin(): Plugin[] {
             !code.includes('__viteRscAsyncHooks')
           ) {
             // for build, we cannot use `import` as it confuses rollup commonjs plugin.
-            return (
+            const output = new MagicString(code)
+            output.prepend(
               (this.environment.mode === 'build' && !isRolldownVite
                 ? `const __viteRscAsyncHooks = require("node:async_hooks");`
                 : `import * as __viteRscAsyncHooks from "node:async_hooks";`) +
-              `globalThis.AsyncLocalStorage = __viteRscAsyncHooks.AsyncLocalStorage;` +
-              code
+                `globalThis.AsyncLocalStorage = __viteRscAsyncHooks.AsyncLocalStorage;`,
             )
+            return {
+              code: output.toString(),
+              map: output.generateMap({ hires: 'boundary' }),
+            }
           }
         },
       },